1. Field of the Invention
The present invention pertains generally to work holders, and more specifically to a work holder having one jaw that is common to plural coacting jaws. In a yet more specific manifestation of the invention, a clamp has a plurality of jaws that interact with at least one additional clamp or fixture to apply forces to a work surface at locations that would otherwise be impractical or impossible to reach.
2. Description of the Related Art
Mankind has, throughout the ages, used available materials in the construction of both essential and non-essential items. This construction has been so refined through the ages that many persons today depend for their entire existence upon these constructed articles. Mankind is, however, quite unique in the animal kingdom in this ability to construct so many different commodities.
In the manufacture or production of commodities, people use many diverse tools to simplify and enable the required processes or events to occur. Since a person is only provided with limited appendages, and these appendages can generally be applied to more useful and valuable purposes, a common need is that of ways to hold an object in place without requiring an extended application of manual force. Frequently, the object being held will be a stock material that is being acted upon in some way, such a machining, drilling, sanding, adhesively or metallurgically bonding, or any of a nearly limitless other assortment of processes and operations, as has been illustrated in the prior art and will be understood to be included herein. Objects that are relatively of the same size or smaller than a clamp or vise are frequently retained by one or more of these clamps with relative ease and simplicity. This is because the jaws of the clamp are generally within a few multiples of size of the object, and the jaws will then be capable of reaching to and apply forces at a sufficient number of points or locations on the object to achieve the desired or required application of force.
Unfortunately, when the object or work becomes relatively larger, the cost of purchasing and storing proportionally larger clamps frequently becomes prohibitive. Instead of trying to purchase and store such giant and bulky clamps, a person will instead rely upon more universal clamps and jigs. When these clamps and jigs are unable to apply a desired or essential force, a person will then be forced to forego the particular application, sometimes forcing full redesign of project and plans.
Common types of clamps include c-clamps, which are so named since the fixed jaw is formed into the general shape of the letter xe2x80x9cCxe2x80x9d, pipe clamps which provide jaws at indeterminate locations along an indeterminate length pipe, and bar clamps, which may be of indeterminate length but which more commonly are between pipe and c-clamps in length. These most common commercially available clamps each have only a few inches of jaw length transverse to the clamping axis, and are consequently able to grab a very limited distance onto an object. Because the length of the bar and c-clamps may be indeterminate, the spacing between jaws may be substantially larger, spanning several feet or more. This ability to adjust the jaw spacing has permitted many smaller enthusiasts or workers to keep on hand such clamps and address many of the requirements for applying force that are encountered within a work shop, irrespective of whether the shop is used for wood, metal, plastic or other stock materials or compositions.
Nevertheless, there has continued to be a particularly vexing problem that is all too frequently encountered. When a large sheet of stock material is to be worked upon and requires application of forces normal to the surface of the sheet, such forces may only be attained readily at points immediately adjacent to the edges of the sheets. This is because those foregoing clamps have short jaw lengths transverse to the force axis. While it is possible to increase the jaw size, this adds substantially to the weight and cost, and limits the application of the clamp to progressively larger objects. Between weight, cost and applicability to only larger work objects, the flexibility that was the benefit of these types of clamps is completely lost.
In order to provide access along the interior of larger planar surfaces, several clamps are available that are configured to cooperatively engage with bar clamps, and then apply forces transverse to the longitudinal bar axis. Such clamps are available, for exemplary purposes, from Bessey and referred to as edge clamps. Other clamps sold under the Bessey name include xe2x80x9cPonyxe2x80x9d veneer press screws, which wrap about a pipe and apply forces transverse thereto. Yet another type of veneer clamp is referenced as the xe2x80x9cJorgensenxe2x80x9d press screw. The teachings of each of these clamps are hereby incorporated herein by reference. However, as is known to those in the art, these clamps are specialty clamps having very specific utility. For example, the xe2x80x9cPonyxe2x80x9d veneer press screws sold by Bessey are applicable only to particular diameters of black pipe, and are incompatible with other types of supports. Similarly, the xe2x80x9cJorgensenxe2x80x9d press screws require a hole in a support through which the screw may pass and be anchored to. Consequently, there is not an opportunity for unlimited adjustment, nor for alternative or diverse application with either of these commercially available clamping devices. Their application and adjustment range are both undesirably limited.
A number of patents also illustrate exemplary clamps, similar to the Bessey clamps referred to herein above. The contents of each of these are incorporated herein by reference for the teachings that are found therein. These patents include U.S. Pat. No. 2,773,303, to Tirone; U.S. Pat. No. 2,991,669 to Stock; U.S. Pat. No. 2,816,586 to Koberle; and U.S. Pat. No. 1,201,888 to Steuber. These patents also suffer from the above described drawbacks.
In a first manifestation, the invention is a clamp having only three jaws, each with a work engaging surface, and an actuator. The second jaw work engaging surface faces the first jaw. The third jaw, which is substantially fixed in location relative to the second jaw, has a work engaging surface generally opposed to theand first jaw work engaging surface. The actuator is coupled to and actuates the first jaw along a travel path.
In a second manifestation, the invention is a combination stand, carrier mounted upon the stand and clamp assembly slidably supported upon the carrier. Means are provided to hold the carrier in a desired position relative to the stand. The clamp assembly consists of only three jaws and a locking mechanism. A first one of the three jaws attaches to an actuating assembly that can be driven with force along a linear path. A work engaging surface faces generally in a first direction along that linear path. A second one of the three jaws attaches at a substantially fixed location along the linear path and has a work engaging surface facing generally opposed to the first jaw work engaging surface. The third jaw attaches at a second substantially fixed location along the linear path and is separated from the second jaw location by the first jaw. The third jaw also has a work engaging surface facing generally opposed to the first jaw work engaging surface. A means is provided for preventing relative motion between clamp and surface of the carrier.
In a third manifestation, the invention is a workpiece and associated support. The workpiece has a first major surface that is spanned by the support. A clamp has a first channel and a second channel nested in and movable relative to the first channel. The clamp second channel rigidly engages the support and the clamp first channel rigidly engages the workpiece.
In a fourth manifestation, the invention is a clamp. According to this manifestation, the clamp has a first u-shaped strap having a coupling and at least one jaw work engaging surface thereon. A second u-shaped strap is nested within the first u-shaped strap and has a coupling and at least one jaw work engaging surface. A means is provided for moving the first u-shaped strap relative to the second u-shaped strap.
Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a plurality of jaws, including in a preferred embodiment at least one jaw nested within an exterior pair of jaws, for alternatively applying a separating force or a compressive force. A preferred configuration is illustrated which readily accommodates a wide variety of available supports that may be used for engagement, in combination with the present invention, to achieve anchoring in previously inaccessible or uneconomical locations.
A first object of the invention is to provide a small and easy to handle clamping attachment that may be used with existing common clamping structures to apply forces normal to and anywhere across a large planar surface. A second object of the invention is to provide this clamp for relatively low cost by avoiding the use or incorporation of difficult-to-manufacture parts. Another object of the present invention is to enable this clamp to be used either as a means for applying normal forces, or, alternatively, as a standard c-clamp. Such alternative use reduces required storage space and reduces the cost per use of the present clamp. A further object of the invention is to fabricate such a clamp that with only a minor additional component may be used for either wood contact or for metal welding exposure. Yet another object of the invention is the reduction of clearance required between a support and work piece within which the clamp may be effective. Yet a further object of the invention is the flexibility of not only clamping across major surfaces spanned by supports, but also being able to cooperatively apply edge forces or other forces transverse to a clamp, and in association with such diverse clamp types as bar, pipe, xe2x80x9ccxe2x80x9d, band and other clamps known in the prior art or even in association with the present clamp.